Electrodeposition of Colloidal Particles on a Rotating Disk Electrode.

The deposition of colloidal particles in electrochemical systems is considered to be a viable process in the synthesis of composite films with unique physico-chemical properties that offer a wide range of engineering applications. The development of this technology requires a fundamental understanding of particle deposition mechanisms in electrochemical systems. A comprehensive model is developed for describing the various mass transport and interfacial kinetic processes involved in the deposition of Brownian colloidal particles on a rotating disk electrode at which a single metal electrodeposition reaction occurs. Theoretical calculations are presented for the electrodeposition of copper and monodisperse colloidal particles under galvanostatic conditions. We find that the rate of particle deposition in simple binary electrolytes, expressed in terms of the dimensionless Sherwood number, is strongly influenced by the current density, Brownian diffusivity, and the zeta potential of the particles. Reduced rates of particle deposition are consistent with diffusiomigration effects. The result of this work is expected to provide a knowledge base for continued investigations on particle deposition mechanisms and support the development of engineering design strategies for achieving composite films with prescribed characteristics.